Splunk® Universal Forwarder

Forwarder Manual

This documentation does not apply to the most recent version of Splunk® Universal Forwarder. For documentation on the most recent version, go to the latest release.

Known issues

This topic lists known issues that are specific to the universal forwarder. For information on fixed issues, see Fixed issues.

Universal forwarder issues

Date filed Issue number Description
2023-03-23 SPL-237740, SPL-226003 When forwarding from an 9.0 instance with useAck enabled, ingestion stops after some time with errors: "Invalid ACK received from indexer="

As a workaround, disable useAck in outputs.conf on the forwarder. After disabling, indexers start to ingest data.

If you need useACK to prevent data loss, disabling autoBatch in outputs.conf can remediate the issue too, but it impacts throughput - no worse than 8.x, but no improvement for 9.0.

2022-12-01 SPL-233535, SPL-231086 UF 9.x Unnecessary user creation during silent installation

Delete etc/passwd manually after installation, create user-seed.conf with new user in SPLUNK_HOME/etc/system/local and restart Splunk

Customer claims that they were able to bypass the issue by using SPLUNKPASSWORD="" option during installation but I was not able to reproduce this example of user-seed.conf: https://drive.google.com/file/d/1GrypUL6719V0tGbw0Mv-u76jUYZ8LBS_/view?usp=sharing

2022-11-03 SPL-232467 SSL UF v9.x SSL Cert Auto-populates into Windows Certificate Store

Make the following changes in server.conf:

Before upgrading:

Save the original setting of [sslConfig] / serverCert if it's set, and then set the following:

[sslConfig] serverCert = C:\Program Files\SplunkUniversalForwarder\etc\auth\new_default.pem

[kvstore] disabled = 1

The file `C:\Program Files\SplunkUniversalForwarder\etc\auth\new_default.pem` must not exist before the upgrade.

After upgrading: Set serverCert back to the original value and restart the universal forwarder. If it was not set before applying the workaround, it can be left unchanged as the universal forwarder will use the newly generated PEM file.

2022-10-25 SPL-232028, SPL-236165, SPL-236166 Windows Defender logs stop being forwarded but other Winevent logs continue to forward until UF is restarted

Restart the UF
2022-10-20 SPL-231793 Crashing in TcpOutEloop thread with assertion_failure="_refCount > 0"



2022-09-08 SPL-229853, SPL-229208 PowerShell Modular input stopped working after UF 9.0 upgrade
2022-07-30 SPL-227653, SPL-231927 UF throws erroneous WARN for KVSTORE SSL misconfiguration on startup - server.conf//sslVerifyServerCert or "Starting migrate-kvstore."

It's safe to ignore the warning or you can disable the kvstore explicitly with server.conf:
disabled = true
2022-06-23 SPL-226019 Warning appears in the universal forwarder whenever any spl command is run: Warning: Attempting to revert the SPLUNK_HOME ownership Warning: Executing "chown -R splunk /opt/splunkforwarder". This warning is expected and will not affect functionality.
2022-06-06 SPL-225379 Ownership of files mentioned in manifest file is splunk:splunk instead of root:root after enabling boot start as root user for initd

When changing UF user, manually chown SPLUNK_HOME to the new user, including first time install/upgrade, or manually enable boot-start.
2022-05-16 SPL-224264, SPL-224265 Splunk UF not starting on Debian 11 (x86_64 and arm64)
2022-04-20 SPL-222917, SPL-230428 Crash in indexer discovery service on search head
2020-11-09 SPL-197140, SPL-234386 UF failed to start on Solaris 11.3 with error: "symbol in6addr_any: referenced symbol not found"

1. Do not upgrade past Splunk 8.0.5 on Solaris 11.3

OR 2. Upgrade to Solaris 11.4

Last modified on 13 March, 2024
Troubleshoot the universal forwarder   Fixed issues

This documentation applies to the following versions of Splunk® Universal Forwarder: 9.0.1

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